Platelet Transfusion Refractoriness Research Articles

Establishment and clinical application of the HLA genotype database of platelet-apheresis donors in Suzhou

The establishment of a platelet-apheresis donor database may provide a feasible solution to improve the efficacy of platelet transfusion in patients with immune platelet transfusion refractoriness (PTR). This study aimed to establish HLA genotype database in Suzhou, to provide HLA-I compatible platelets for PTR patients to ensure the safety and effectiveness of platelet transfusions. We used a polymerase chain reaction sequence-based typing (PCR-SBT) method to establish the database by performing high-resolution HLA-A, -B, and –C genotyping on 900 platelet-apheresis donors. HLA-I antibody was detected in patients using a Luminex device, and HLA-I gene matching was performed by an HLA-Matchmaker. We found that the highest frequency of the HLA-A allele was A*11:01 (17.06 %), followed by A*24:02 (14.67 %) and A*02:01 (13.61 %). The highest frequency of the HLA-B allele was B*46:01 (9.78 %), followed by B*40:01 (8.39 %) and B*13:02 (33 %). After the detection of platelet antibodies in 74 patients with immune PTR, we found 30 HLA-A antibodies and 48 HLA-B antibodies, and there were a variety of high frequency antibodies whose alleles were low in the donor database, such as HLA-A*68:02, and B*57:01. After avoiding donor-specific antibodies (DSA) matching, 102 of 209 platelet-compatible transfusions were effective, resulting in an effective rate of 48.8 %, which significantly improved the efficacy of platelet transfusion. The establishment of a platelet donor database is of great significance to improve the therapeutic effect of platelet transfusion in patients with hematologic disorder, and save blood resources, and it is also the premise and guarantee of precise platelet transfusion.

The importance of ABO in platelet refractoriness, an often overlooked option.

ABO-non-identical (ni) platelets provide less of an increase in platelet count and may increase the length of patient transfusions. The paper by Han and Badami showed that ABO-ni platelets may be a risk factor for immune platelet transfusion refractoriness. Commentary on: Han etal. ABO non-identical platelet transfusions, immune platelet refractoriness and platelet support. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19359.

[Analysis of transfusion effect of different platelet matching schemes in patients with platelet transfusion refractoriness].

Objective: To analyze the transfusion effect of different platelet matching schemes in patients with platelet transfusion refractoriness (PTR). Methods: A total of 94 patients with PTR received by Taiyuan Blood Center from January to December 2021 were retrospectively analyzed, including 26 males and 68 females, aged 53(34,66) years. Platelet antibody screening was performed by enzyme-linked immunosorbent assay (ELISA). For patients with positive human leukocyte antigen (HLA) class Ⅰ antibodies, Luminex platform liquid chip assay was used to identify the specificity of antibodies, and platelets with missing allelic expression antigen corresponding to their specific antibodies were found in the platelet donor gene database established in our laboratory. For patients with negative class HLA-Ⅰ antibody screening, medium and high-resolution HLA-A and B alleles were genotyped by polymerase chain reaction restriction sequence specific oligonucleotide (PCR-SSO), and the compatible platelets were searched from the platelet donor gene database by HLA cross-reactive group genotype matching scheme or directly selected by serological cross-matching. The PCI compliance rate and total transfusion effective rate of different mismatch site groups and different matching scheme groups were statistically analyzed. Results: Platelet antibody was detected in 39 of 94 PTR patients with a positive rate of 41.5%, and all of them were HLA-Ⅰ antibodies, and 1 case was accompanied by human platelet antigen (HPA) antibody. A total of 134 times of compatible platelets were supplied to 39 patients with HLA-Ⅰ antibody positive by using antibody avoidance matching method. And the total effective rate of transfusion was 97.8% (131/134); The PCI compliance rates of HLA-A antigen mismatch, HLA-B antigen mismatch and HLA-A and B antigen mismatch groups were 81.6% (31/38), 86.5% (32/37) and 78.6% (22/28), respectively. The total effective rate of transfusion was 97.4% (37/38), 94.6% (35/37) and 100% (28/28), respectively, with no statistical significance (all P>0.05). A total of 118 times of compatible platelets were provided by HLA antigen cross-reaction group genotype matching and serological cross-matching, 90 transfusion effects were collected during follow-up, and the total effective rate was 76.7% (69/90). Conclusion: The combination of different platelet matching schemes can improve the PCI compliance rate and the total effective rate of transfusion in PTR patients.

ABO non-identical platelet transfusions, immune platelet refractoriness and platelet support.

ABO-non-identical (ABO-ni) platelets may be another risk factor for immune platelet transfusion refractoriness (i-PTR). We examined the effect of such platelets on i-PTR and subsequent platelet support through retrospective analysis of 17 322 New Zealand patients receiving ≥1 platelets. Immune PTR was defined as PTR with anti-HLA-I/HPA positivity. Univariate and multivariate analyses determined the independent risk factors for i-PTR. One hundred and eighty-eight patients (1.1%) had i-PTR and received more ABO-ni platelets than non-refractory patients (53.2% vs. 29.5%; p < 0.001). More non-O than group O patients had received ABO-ni platelets before i-PTR diagnosis (67.6% vs. 32.5%; p < 0.001). Female sex (p < 0.001), age ≤ 60 years (p = 0.004), haematology patients (p < 0.001) and ≥2 ABO-ni platelets (p < 0.001) were the independent risk factors for i-PTR. More i-PTR patients with anti-HLA-I were non-O compared to group O (90.1% vs. 75.3%; p = 0.007). More with anti-HLA-I + anti-HPA were group O than non-O (24.7% vs. 9.0%; p = 0.003). ABO-ni platelet-exposed i-PTR patients required matched platelets for longer than those receiving only ABO-i platelets (96.5 vs. 59.0 days; p = 0.02). ABO-ni platelets may be a risk factor for i-PTR with dose effect. ABO-i platelets should be considered whenever possible for at-risk patients.

Avatrombopag for the salvage treatment of platelet transfusion refractoriness.

Platelet transfusion refractoriness (PTR) is a life-threatening and intractable condition in hematological patients. Thrombopoietin receptor agonists such as avatrombopag promote platelet production and modulate immune intolerance. However, its application in PTR has not been extensively studied. We aimed to compare the platelet response (PR) as well as bleeding events and mortality rate between the best available therapies (BATs) and avatrombopag (Ava) treatments in refractory PTR patients. A total of 71 refractory PTR patients were enrolled at Nanfang Hospital. Intravenous immunoglobulin, steroids, and human leucocyte antigen-matched platelet transfusions were administered to 30 patients in the BATs group. The Ava group included 41 patients. Data of refractory PTR patients were retrospectively collected. The primary endpoint was PR (defined as an increase of platelet count to ⩾50 × 109/L without platelet transfusion support for 7 consecutive days). Secondary endpoints included platelet-transfusion independence rate, cumulative platelet transfusion units, World Health Organization bleeding grades, adverse events, overall survival (OS), and bleeding event-free survival (EFS). There were 75.6% and 13.3% refractory PTR patients who reached PR within 3 months in Ava and BATs groups. The median platelet counts were significantly higher in Ava group from day 7. Platelet-transfusion independence rate in Ava was higher than BATs group. The median cumulative platelet transfusion unit in Ava was lower than that of BATs group. The OS and bleeding events-free EFS rate of Ava group improved within 3 months as compared to BATs group. Cox proportional hazards regression analysis revealed that Ava therapy was a protective factor for the OS and EFS. No primary disease progression or termination of avatrombopag was observed due to intolerability. Our study suggests that avatrombopag is an effective and safe treatment option for refractory PTR patients.

Identification of Anti-HLA-C Autoantibody As Risk Factor for Primary Platelet Transfusion Refractoriness in Patients with Hematologic Disorders

Platelet transfusion is an important supporting treatment for hematologic disorders, especially in bone marrow failure disease and post-chemotherapy myelosuppression. However, in patients experienced multiple transfusions, platelet transfusion refractoriness (PTR) occasionally happened. Up to date, many factors had been explored contribute to the PTR, including infections, splenomegaly, antibodies against human leukocyte antigen class I (HLA-I) and antibodies against human platelet antigens (HPA). Based on our clinical practice, we also discovered that many cases had experienced primary PTR (who have been experienced PTR since the first platelet transfusion). Those patients suffered from severe thrombocytopenia can only be effectively corrected by cross-matching platelet transfusion. To our knowledge, anti-HLA-I-A and B antibodies had been reported to be in reference to immune-mediated PTR, while there are no conclusions about primary PTR. Herein, we identified anti-HLA-C autoantibodies was an independent risk factor for the primary PTR in patients with hematologic disorders, even refractoriness to cross-matching platelet transfusion or HLA-selected platelet transfusion. We retrospectively reviewed the patients that had HLA high resolution genotyping test report (potential for hematopoietic stem cell transplantation), and along with a donor-specific HLA antibodies (DSA) test or PRA testing potential for cross-matching platelet transfusion in our department between January 2019 and March 2023. 114 patients were enrolled, with a median age of 40 (14-80) years old, and the composition of disorders were aplastic anemia (65.8%), leukemia (21.9%), myelodysplastic syndrome (8.8%) and other (3.5%) (Fig A). Post-transfusion platelet efficacy was evaluated by the calculation of corrected count increment (CCI). The overall transfusion effective rate was 69.23% in this cohort, while 18.8% failed response from the first transfusion. Logistic regression analysis showed that only anti-HLA-I antibody contribute to the ineffectiveness of first and overall platelet transfusion (Fig B-E). In patients with positive anti-HLA-I antibodies, there were 35, 48 and 32 patients positive for anti-HLA-A, B and C antibodies, respectively (Fig A). Meanwhile, we surprisingly found that there were also 6 patients have anti-HLA-I autoantibody, including 6 on HLA-C and 1 have both HLA-A and C. To distinguish and gain a better understanding of the value of anti-HLA autoantibody in both TR and PTR, we further analyzed each locus of HLA-I and found that either anti-HLA-A, HLA-B or HLA-C antibody contribute to the ineffective to the overall and first platelet transfusion (Fig F-G), while logistic regression analysis revealed that only anti-HLA-C antibody was the independent risk factor (Fig H-K). We performed a logistic regression analysis with factors of anti-HLA-A, B antibody and anti-HLA-C autoantibody, and results showed that the association between positive anti-HLA-C autoantibody and the occurrence of PTR was significant ( P=0.008) (Fig J-M), while a difference approached the significance was also observed in overall platelet transfusion analysis ( P=0.054) (Fig N-O). In detail, we found that the effective overall platelet transfusion in the 6 patients who had anti-HLA-C autoantibodies was 20% (18 out of 90 transfusion), while for patients only have anti-HLA-C non-autoantibodies, it was 59.76% (47 out of 246 transfusion), a significant difference was observed ( P&amp;lt;0.001) (Fig P). For 3 patients with positive anti-HLA-C autoantibodies, all experience ineffective cross-matching platelet transfusion; while for the patients whom without anti-HLA-C autoantibodies, 21 patients experience cross-matching platelet transfusion and 17 of them response quite well, whit a significantly differences ( P=0.017) (Fig Q). In summary, our study demonstrated that positive anti-HLA-C autoantibody had a significant association with the occurrence of primary and overall PTR. The effects of cross-matching platelet transfusions in these patients are also unsatisfactory. To reduce the occurrence of PTR, our results suggested that it is necessary to anticipate the occurrence of PTR in patients with anti-HLA-C autoantibody positivity. Meanwhile, mechanisms should be explored and ways should be sought to lower the levels of such autoantibodies.

Donor-Specific Antibody Mean Fluorescence Intensity Threshold Predicts Platelet Transfusion Response in HLA-Alloimmunized Patients

Introduction:Patients with platelet transfusion refractoriness (PTR) due to HLA-alloimmunization respond to HLA-matched platelets. However, 4/4 HLA-matched platelets or platelets without donor-recipient antigenic mismatches are rarely available. Further, in severe HLA-alloimmunization, it is difficult to find donor products which do not contain antigens to which the recipient has developed antibodies ( i.e. antibody specificity prediction, ASP method). Hence, studies have evaluated platelet transfusion responsiveness in the presence of ≥1 donor specific antibodies (DSAs) to widen donor pools, a strategy termed permissive mismatching (PERMM). Using established semi-quantitative techniques for HLA-antibody detection, we sought to identify a cumulative DSA threshold which predicted platelet corrected count increment (CCI) failure despite PERMM. Methods:We retrospectively reviewed platelet transfusions among patients with HLA-alloimmunization and suspected PTR at the University of Washington/Fred Hutchinson Cancer Center from 2021-2023. HLA Class I antibodies were detected using a solid-phase single antigen bead assay (One Lambda) on the Luminex platform with individual antibody strengths measured by the mean fluorescence intensity (MFI). The calculated panel reactive antibodies (cPRA) were defined as the proportion of donors against whom recipients had antibodies. Transfusions were categorized as HLA matched, PERMM (DSA MFI&amp;gt;0), or random donor platelets (HLA-type unknown). CCI was calculated as described by Cohn ASH 2020. Results: Of 420 patients suspected to have PTR, 75 had cPRA &amp;gt; 50% and received ≥3 HLA-selected platelet transfusions. Of the 2726 transfusions these patients received, 1198 were excluded due to unavailability of post-transfusion platelet counts within 2 hours or due to multiple transfusions occurring between platelet counts. Ultimately, 1528 transfusions were analyzed (Panel A). In 1031 PERMM transfusions, the cumulative MFI was a stronger predictor of CCI at 2 hours than cPRA or the number of mismatched DSA (coefficients of determination or R2 of 7.3%, 2%, and 0.4%, respectively). We then examined the spectrum of cumulative MFIs to identify a threshold MFI predicting transfusion success/failure among the PERMM products. PERMM platelet transfusions in recipients with DSA MFIs of up to 5000 generated CCIs similar to HLA-matched platelets. However, CCI was significantly different between MFI &amp;lt;10,000 (median CCI 17,783) and MFI ≥10,000 (median CCI 3753) (Panel B). We then stratified data by splenomegaly, a significant non-immunologic cause of PTR (23.2% of transfusions, R2 15.8% for CCI prediction). Of the transfusions not affected by splenomegaly, 9.6% did not generate an adequate platelet response (defined as a CCI &amp;gt;5000) across all MFIs. This failure rate increased to 33.3%, 40.8%, and 52.8% among transfusions in recipients with MFIs &amp;gt;5000, &amp;gt;7500, and &amp;gt;10,000, respectively. After multiple testing correction, MFI of several individual DSAs (A1, A2, A24, A68, B8, B37, B39, B44, B51, B57, and B62) were also found to be significant predictors of CCI using linear regression ( n ranging 32-193, R2 ranging 6-33%). Conclusions: This is the largest study to date evaluating optimal MFI thresholds of DSAs for permissive HLA mismatching in the context of platelet transfusions. Cumulative DSA MFIs demonstrated a dose response effect with lower MFIs generating better CCIs. In our patient cohort overall, and when stratified by splenomegaly, we identified a threshold for cumulative DSA MFIs of 10,000, under which &amp;gt;50% of transfusions resulted in an adequate CCI. This MFI threshold (&amp;gt;10,000) has been implicated in HLA mismatched solid organ transplant rejections (Kallon, Transf. Med. 2020) as well as in a pooled analysis of smaller HLA-selected platelet transfusion studies conducted by our group (unpublished). If incorporated into a transfusion strategy, this MFI threshold may perform better than units chosen based on the number of mismatched DSAs alone or random donor platelets and widen the donor pool. Identifying the impact of specific HLA antibodies on CCIs needs further study. Studies are also underway to correlate cumulative DSA MFIs with complement activation (C1q levels) as a possible mechanistic explanation for the differences noted across the MFI threshold of 10,000 in our study.

Impact of Non-Immune Factors on Platelet Transfusion Responses in an Allo-Immunized Cohort

Background: Patients with hematologic malignancies and/or hematopoietic stem cell transplantation (HSCT) recipients often require platelet transfusion support for extended periods. This can result in platelet transfusion refractoriness (PTR) from HLA alloimmunization in up to 30% of individuals. These medically complex patients may also have splenomegaly, fevers and other factors which contribute to PTR. Consequently, they may demonstrate variability in immediate platelet recovery (at 0-2 hours post-transfusion), and in subsequent platelet consumption (at 18-24 hours) despite receiving HLA-selected platelet products. We sought to examine patient and product related factors which impacted platelet transfusion response in a cohort of HLA-alloimmunized platelet transfusion refractory patients. Methods: From April 2021 to June 2023, HLA-alloimmunized (PRA &amp;gt;50%) subjects who required three or more HLA selected platelet units were identified at the Fred Hutchinson Cancer Center/University of Washington. Data were obtained on patient demographics, diagnoses, Panel Reactive Antibodies (PRA %) and factors shown to be associated with poor platelet responses (spleen size, disseminated intravascular coagulation (DIC), bleeding, selected medications, history of hematopoietic stem cell transplant (HSCT) and/or graft versus host disease (GVHD), ABO compatibility, and product age). Platelet corrected count increments (CCI) were calculated for each transfusion. Non-HLA factors potentially contributing to CCIs at 0-2 and 18-24 hours post-transfusion were compared among HLA-compatible (either 4/4 HLA matched without HLA antigen mismatches, or with permissive mismatches (defined as cumulative a mean fluorescent intensity (MFI) &amp;lt;10,000 on the Luminex donor specific HLA antibody testing platform)) and HLA incompatible transfusions (cumulative MFI &amp;gt;10,000 or random donor apheresis products). Results: Of the 420 patients screened, 75 had sufficient records for inclusion. These subjects received 2729 platelet transfusions, an average of 36 transfusions per patient over 5.2 (± 4.1) months. Post transfusion platelet counts were available for 1528 transfusions. All platelet products were leukoreduced, irradiated, single donor apheresis products. Patients were predominantly Caucasian (70.7%; n=53/75), female (82.7%; n=62/75), aged 57 (±14.9) years. The primary diagnosis was Acute myelogenous leukemia or myeloproliferative disorder in most cases (88%; n=66/75). 58.7% (n=44/75) of patients were HSCT recipients (3 auto-; 41 allo-HSCT). Average PRA among patients was 72.4%±22.2%. 25 patients had splenomegaly. Among HLA-compatible transfusions, average CCIs at 0-2 and 18-24 hours were 17,088 and 6,666. In HLA-mismatched/random donor transfusions, average CCIs at 0-2 and 18-24 hours were 11,489 and 2,786; HLA compatible products increased CCIs by 5,599 and 3880 at 0-2 and 18-24 hours. In both groups splenomegaly had the most consistent association with poor CCI at both time intervals (Figures A and B). Conclusions: In this cohort of individuals with HLA-alloimmunization mediated PTR, the administration of HLA-compatible products offset the impact of other detrimental factors generating adequate CCIs at 0-2 and 18-24 hours. Among patients with splenomegaly, CCIs were lower despite HLA compatible product administration. In the same individuals, HLA-incompatible/random donor products negatively impacted CCIs overall and the negative effect of other concomitant non-immune/product-related factors was additive.Our data highlights the need to account for non-HLA related conditions while evaluating CCI response following each HLA-selected product transfusion, and to further explore any interactions among such factors. Next steps include conducting a multivariate analysis and developing a predictive model for platelet transfusion response in HLA-alloimmunized recipients who have concomitant non-immune or product related risk factors.

Simvastatin with Intrathecal Dexamethasone Reduces Neurotoxicity in Adults Receiving Chimeric Antigen Receptor (CAR) T-Cells Treatment

Background Chimeric antigen receptor (CAR) T-celltherapy has become the standard of care for many relapsed/refractory hematological malignancies. There are significant associated side effects, most importantly cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) that can limit its use in older and vulnerable populations. The rate of ICANS with axicabtagene ciloleucel (axi-cel) in the pivotal studies for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) was approximately 60% with grade 3 or higher (≥ G3) in the range of 19-28%. Similarly, with brexucabtagene autoleucel (brexu-cel), ICANS also occurred in approximately 60% with ≥ G3 occurring in 26-31% of patients. The mechanism underlying ICANS remains unclear. The current hypothesis is that endothelial injury caused by systemic immune activation leads to the breakdown of the blood-brain barrier with the influx of pro-inflammatory cytokines into the CSF and subsequent activation of resident immune cells and neuroglial cells leading to local production of cytokines and the clinical syndrome observed. ICANS is treated with systemic steroids that have good central nervous system (CNS) penetration. Statins have been shown to stabilize the endothelium and have anti-inflammatory effects. We are currently evaluating the safety and feasibility of administering simvastatin in addition to intrathecal dexamethasone to decrease the incidence and/or severity of neurotoxicity in CAR-T recipients and we are herein reporting preliminary results. Methods This is a feasibility study (NCT04514029) combining simvastatin 40 mg daily, starting 5 days prior to apheresis and continuing through day +30 with dexamethasone (8 mg) delivered intrathecally (IT) on days -1 and +6 in relation to CAR T-cell infusion. Adult patients (age ≥18 years) receiving axi-cel or brexu-cel for FDA-approved indications are included. The primary endpoint is the percentage of patients who complete 80% of this therapy (pills and intrathecal). Secondary endpoints include the incidence of CRS and ICANS as well as overall response rates (ORR). Results At the time of data cutoff, a total of 15 patients who received treatment with axi-cel or brexu-cel and completed follow-up were enrolled. Baseline demographics and clinical characteristics are summarized in Table 1. Among patients who received axi-cel, 10 patients had DLBCL and 1 patient had FL. For brexu-cel, 2 patients had mantle cell lymphoma (MCL) and 2 had B-acute lymphoblastic leukemia (B-ALL). Median prior lines of treatment was 3 (range 2 to 7) and 11 patients (46.7%) had progressive disease at the time of the treatment. Analysis of baseline inflammatory markers prior to the cell infusion showed that 2 patients (13.3%) had elevated lactate dehydrogenase (LDH; upper limit normal 250 U/L; median 180, range 100 to 279). Eight patients (53.3%) had elevated C-reactive protein (CRP; median 9.24 mg/L, range &amp;lt;3 to 67.8). Ferritin was elevated in 6 patients (40%) (median 382, range 34 to 1749). All patients received &amp;gt; 80% of the total assigned doses. One patient was unable to receive intrathecal therapy due to thrombocytopenia with platelet transfusion refractoriness. All evaluable patients completed oral simvastatin with no patients requiring dose reductions. CRS occurred in 13 patients (86.7%), with ≥ G3 occurring in 1 patient (6.7%). Tocilizumab (8 mg/kg) was administered to 11 patients (73.3%) with the median number of doses being 1 (range 1 to 4). ICANS occurred in 4 patients (26.7%), with ≥ G3 occurring in 2 patients (13.3%) - one G3 and one G4 in the patient who was unable to receive IT therapy. Glucocorticoids were used in 3 patients (20%) for the management of ICANS. There were no grade 4 CRS events and no deaths related to CRS or ICANS. One patient had a vasovagal syncopal episode prior to the beginning of a lumbar puncture. There were no other ≥ G3 AEs associated with the administration of simvastatin or IT dexamethasone. One patient with Richter's had progressive disease at day 30, 4 patients had partial remission, and 10 patients had a complete remission for an ORR of 93%. Conclusions Preliminary results show that simvastatin and intrathecal dexamethasone appear to be feasible, safe, and effective in reducing the incidence and severity of ICANS in patients receiving axi-cel and brexu-cel.

Changes in inflammatory responses and autophagy during apheresis platelet preservation and their correlation with platelet transfusion refractoriness in patients with acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is a common hematopoietic malignancy, and platelet transfusion plays a crucial role in its treatment. This study aimed to investigate the changes in inflammatory response and autophagy during the preservation of apheresis platelets (AP) and their correlation with platelet transfusion refractoriness (PTR) in ALL. ALL patients were included, and APs were categorized based on the preservation period (day 0, day 1, days 2-3, and days 4-5). The activation factors procaspase-activating compound 1 (PAC-1) and P-selectin (CD62P), AP aggregation function, inflammation levels (interleukin 1 beta [IL-1β], interleukin 6 [IL-6], tumor necrosis factor alpha [TNF-α] and NOD-like receptor thermal protein domain associated protein 3 [NLRP3]), and autophagy-related genes (p62) during AP preservation were assessed. Following co-culturing APs with peripheral blood mononuclear cells (PBMCs), specific activation markers were studied to observe APs influence on immune cells activation. The effectiveness of platelet transfusion was assessed, and risk factors for PTR were analyzed. As the storage duration of AP increased, the activation factors, coagulation factor activity, inflammation levels, and the activation of immune cells in AP increased, while fibrinogen levels and AP aggregation function decreased. The expression levels of autophagy-related genes (the autophagy marker light chain 3B gene [LC3B] and Beclin 1 gene) decreased with prolongation preservation. The effective rate of AP transfusion in ALL patients was 68.21%. AP preservation time, IL-6, p62, and Beclin 1 were identified as independent risk factors affecting PTR in ALL patients. In conclusion, during AP preservation, inflammation, autophagy, and activation of immune cells were observed to increase. AP preservation time, IL-6, p62, and Beclin 1 were independent risk factors for PTR.

Incidence and Role of Recipient-Specific Antibodies in Allogeneic Hematopoietic Cell Transplantation from Mismatched Related Donors

High titer of donor-specific antibodies (DSAs) increases the risk of graft rejection after mismatched related hematopoietic cell transplantation (HCT). There are no data regarding the incidence of anti-HLA recipient-specific antibodies (RSAs) and their role after transplantation. Here we aimed to identify the incidence of RSAs in a mismatched related hematopoietic cell donor population and their possible impact on immune-mediated complications, such as acute graft-versus-host disease (aGVHD), and complications resulting from endothelial injury, such as transplantation-associated thrombotic microangiopathy (TA-TMA) and veno-occlusive disease (VOD). We prospectively analyzed the incidence of anti-HLA antibodies in 28 mismatched related pairs of recipients and their donors who underwent HCT at our center between 2020 and 2022. In positive samples screened for anti-HLA class I and/or II antibodies, the specificity of the HLA antibodies was analyzed. All recipients had a hematologic malignancy and received a myeloablative conditioning regimen and immunosuppression consisting of post-transplantation cyclophosphamide, tacrolimus, and mycophenolate mofetil. Patients were tested for TA-TMA and aGVHD development during routine post-transplantation visits up to 100 days post-transplantation. We used modified Jodele criteria for TA-TMA diagnosis, and based aGVHD grading on the MAGIC criteria. VOD was assessed using the European Society for Blood and Marrow Transplantation. Anti-HLA antibodies were detected in 12 donors (43%) and in 9 recipients (32%). There were no significant differences between donors and recipients according to age (median, 42 years [range, 17 to 69 years] versus 39 years [range, 8 to 68 years]), sex, or pregnancy history. No transfusion history was noted in the donor group (P < .05). RSA antibodies were present more often than DSAs and were detected in 9 out of 12 (75%) anti-HLA-positive donors and in only 2 out of 9 (22%) recipients, respectively (P < .05). During the follow-up, 11 patients (39%) developed aGVHD, including grade I-II in 9 (32%) and grade III-IV in 2 (7%). Twelve patients (43%) met the criteria for TA-TMA, and only 1 patient (3.5%) was diagnosed with VOD by day 100 post-HCT. RSAs were detected significantly more often in the TA-TMA group; among 12 patients diagnosed with TA-TMA, 7 (58%) had RSAs (P < .05). We did not find a correlation between RSAs and aGVHD. The patient with VOD did not have an RSA-positive donor. There was no difference in membrane attack complex (MAC) concentration in the RSA-positive group on day 30 and day 60 post-HCT; however, there was a trend toward higher MAC concentration in the RSA-positive group on day 100 (median, 912 ng/mL [range, 788 to 1120 ng/mL] versus 616 ng/mL [range, 352 to 1244 ng/mL]; P=.055). Patients with RSA suffered more often from platelet and red blood cell decreases or transfusion refractoriness, and increased lactate dehydrogenase activity was observed in all RSA-positive cases. The donor immune status and the presence of RSA may be associated with higher rates of TA-TMA in mismatched HCT recipients. Antibody-mediated complement activation might be an additional factor influencing TA-TMA occurrence.

First platelet transfusion refractoriness in a patient with acute myelocytic leukemia: A case report

Time series analysis is a valuable tool in epidemiology that complements the classical epidemiological models in two different ways: Prediction and forecast. Prediction is related to explaining past and current data based on various internal and external influences that may or may not have a causative role. Forecasting is an exploration of the possible future values based on the predictive ability of the model and hypothesized future values of the external and/or internal influences. The time series analysis approach has the advantage of being easier to use (in the cases of more straightforward and linear models such as Auto-Regressive Integrated Moving Average). Still, it is limited in forecasting time, unlike the classical models such as Susceptible-Exposed-Infectious-Removed. Its applicability in forecasting comes from its better accuracy for short-term prediction. In its basic form, it does not assume much theoretical knowledge of the mechanisms of spreading and mutating pathogens or the reaction of people and regulatory structures (governments, companies, etc. ). Instead, it estimates from the data directly. Its predictive ability allows testing hypotheses for different factors that positively or negatively contribute to the pandemic spread; be it school closures, emerging variants, etc. It can be used in mortality or hospital risk estimation from new cases, seroprevalence studies, assessing properties of emerging variants, and estimating excess mortality and its relationship with a pandemic.

P‐IG‐24 | Immune‐Mediated Platelet Transfusion Refractoriness Complicated by Panagglutinin and Prozone Effect: A Case Report

P‐IG‐24 | Immune‐Mediated Platelet Transfusion Refractoriness Complicated by Panagglutinin and Prozone Effect: A Case Report

Successful allogeneic hematopoietic stem cell transplantation in a patient with type I CD36 deficiency: a case study and literature review.

CD36-deficient individuals may produce anti-CD36 antibodies through antigenic exposure to CD36, in situations including blood transfusions. Therefore, allogeneic hematopoietic stem cell transplantation (HSCT) from CD36-positive donors to CD36-negative patients remains a challenge. A 64-year-old man with acute myeloid leukemia became refractory to platelet transfusions during chemotherapy. Anti-CD36 antibodies without anti-HLA antibodies were detected in serum, and the absence of CD36 expression on platelets and monocytes confirmed type I CD36 deficiency. The patient achieved complete remission, and received maintenance therapy with CD36-negative platelet transfusions. However, he relapsed soon afterward, and thus underwent peripheral blood stem cell transplantation (PBSCT) from a CD36-positive unrelated donor. The anti-CD36 antibody titer had decreased before the transplant, and the PBSCT-course was uneventful. The patient has been well without any complications associated with CD36 status mismatch. The few reports of allogeneic HSCT in patients with CD36 deficiency have suggested that anti-CD36 antibodies could be involved in several post-transplant complications, such as delayed platelet recovery, transfusion refractoriness, and transfusion-related acute lung injury. Our present case confirmed that stem cell transplantation from CD36-positive donors to negative patients is feasible, when it includes careful prior assessment of anti-CD36 antibody titers and interventions to attenuate them.

High-Throughput CD36 Phenotyping on Human Platelets Based on Sandwich ELISA and Mutant Gene Analysis

Background: CD36 deficiency is closely associated with fetal/neonatal alloimmune thrombocytopenia, platelet transfusion refractoriness, and other hemorrhage disorders, particularly in Asian and African populations. There is a clinical need for rapid and high-throughput methods of platelet CD36 (pCD36) phenotyping to improve the availability of CD36 typing of donors and assist clinical blood transfusions for patients with anti-CD36 antibodies. Such methods can also support the establishment of databases of pCD36-negative phenotypes. Study Design and Methods: A sandwich enzyme-linked immunosorbent assay (ELISA) for CD36 phenotyping of human platelets was developed using anti-CD36 monoclonal antibodies. The reliability of the assay was evaluated by calculating the intra-assay and inter-assay coefficients of variation (CV). A total of 1,691 anticoagulant whole blood samples from healthy blood donors were randomly selected. PCD36 expression was measured using a sandwich ELISA. PCD36 deficiency was confirmed by flow cytometry (FC). Mutations underlying pCD36 deficiency were identified using polymerase chain reaction sequence-based typing (PCR-SBT). Results: The sandwich ELISA for pCD36 phenotyping had high reliability (intra-assay CV, 2.1–4.8%; inter-assay CV, 2.3–5.2%). The sandwich ELISA was used to screen for CD36 expression on platelets isolated from 1,691 healthy blood donors. Of these, 36 samples were pCD36-negative. FC demonstrated absence of CD36 expression on monocytes in three of the 36 cases. In the present study population, the frequency of CD36 deficiency was 2.13% (36/1,691), of which 0.18% (3/1,691) was type I deficiency and 1.95% (33/1,691) was type II deficiency. In addition, we used PCR-SBT to characterize the gene mutations in exons 3–14 of the CD36 gene in 27 cases of CD36 deficiency and discovered 10 types of mutations in 13 pCD36-negative samples. Conclusion: The present study describes the development and characterization of a highly reliable sandwich ELISA for high-throughput screening for pCD36 expression. This novel method is feasible for clinical applications and provides a useful tool for the establishment of databases of pCD36-negative phenotype donors.

Neonatal Intensive Care Unit Patients Receiving More Than 25 Platelet Transfusions.

A few patients in neonatal intensive care units (NICU) receive numerous platelet transfusions. These patients can become refractory, defined as transfusions of ≥10 mL/kg failing to increase the platelet count by at least 5,000/µL. Causes of, and best treatments for, platelet transfusion refractoriness in neonates have not been defined. Multi-NICU multiyear retrospective analysis of neonates receiving >25 platelet transfusions. Eight neonates received 29 to 52 platelet transfusions. All eight were blood group O. Five had sepsis, four were very small for gestational age, four had bowel resections, two Noonan syndrome, two had cytomegalovirus infection. All eight had some (19-73%) refractory transfusions. Many (2-69%) of the transfusions were ordered when the platelet count was >50,000/µL. Higher posttransfusion counts occurred after ABO-identical transfusions (p = 0.026). Three of the eight had late NICU deaths related to respiratory failure; all five survivors had severe bronchopulmonary dysplasia requiring tracheostomy for prolonged ventilator management. Neonates who are high users of platelet transfusions appear to be at high risk for poor outcomes, especially respiratory failure. Future studies will examine whether group O neonates are more likely to develop refractoriness and whether certain neonates would have a higher magnitude of posttransfusion rise if they received ABO-identical donor platelets. · Many of the platelet transfusions given in the NICU are given to a small subset of patients.. · Refractoriness to platelet transfusions is common among these very high recipients.. · Neonates who are high users of platelet transfusions appear to be at high risk for poor outcomes..

Genetic landscape of human platelet antigen variants in the Indian population analysed from 1029 whole genomes

AbstractGenetic variants in human platelet antigens (HPAs) considered allo‐ or auto antigens are associated with various disorders, including neonatal alloimmune thrombocytopenia, platelet transfusion refractoriness and post‐transfusion purpura. Although global differences in genotype frequencies were observed, the distributions of HPA variants in the Indian population are largely unknown. This study aims to explore the landscape of HPA variants in India to provide a basis for risk assessment and management of related complications. Population‐specific frequencies of genetic variants associated with the 35 classes of HPAs (HPA‐1 to HPA‐35) were estimated by systematically analysing genomic variations of 1029 healthy Indian individuals as well as from global population genome datasets. Allele frequencies of the most clinically relevant HPA systems in the Indian population were found as follows, HPA‐1a – 0.884, HPA‐1b – 0.117, HPA‐2a – 0.941, HPA‐2b – 0.059, HPA‐3a – 0.653, HPA‐3b – 0.347, HPA‐4a – 0.999, HPA‐4b – 0.0010, HPA‐5a – 0.923, HPA‐5b – 0.077, HPA‐6a – 0.998, HPA‐6b – 0.002, HPA‐15a – 0.582 and HPA‐15b – 0.418. This study provides the first comprehensive analysis of HPA allele and genotype frequencies using large scale representative whole genome sequencing data of the Indian population.

A meta-analysis of risk factors associated with platelet transfusion refractoriness.

Platelet transfusion refractoriness (PTR) remains an intractable issue in clinical practice, and is common in hematological patients. At present, it is believed that both immune and non-immune factors play a role. We conducted a meta-analysis of various risk factors which may contribute to PTR. PubMed, Embase, Cochrane library, and Web of Science were selected as research database platforms. Citations included were further assessed for quality and bias using the Newcastle-Ottawa Scale. All analyses were performed using Review Manager Version 5.4 and STATA 16.0. The preliminary search revealed 1069 publications, and 17 (5929 patients in total) were ultimately included in the quantitative analysis. The following variables were associated with the occurrence of PTR: fever (OR = 2.26, 95%CI 2.00-2.55, p < 0.00001), bleeding (OR = 2.10, 95%CI 1.36-3.24, p = 0.0008), female sex (OR = 2.06, 95%CI 1.13-3.75, p = 0.02), antibiotic use (OR = 2.94, 95%CI 1.54-5.59, p = 0.001), and infection (OR = 2.19, 95%CI 1.20-4.03, p = 0.01). Antibodies involved in immune activation were a higher risk factor (OR = 4.17, 95%CI 2.36-7.36, p < 0.00001), and splenomegaly was nearly significant (OR = 1.73, 95%CI 0.97-3.07, p = 0.06). We identified some important risk factors for PTR, but further research is needed to identify the many other possible elements that may contribute to or mediate PTR.

Therapeutic Efficacy of Platelet Transfusion and Analysis of Influencing Factors in 364 patients

Introduction: The aims of this study were to observe the therapeutic effect of platelet (PLT) transfusion and to analyze influencing factors for the sake of providing useful clues for improving the efficacy of PLT transfusion. Methods: Included in this study were patients who received PLT transfusion in the affiliated hospital of Nantong University. Patients’ sex, age, height, weight, PLT transfusion status, and 20–24-h PLT count before and after PLT transfusion were collected to calculate the PLT corrected count increment values before and after PLT transfusion. Solid-phase red cell adherence assay was used to determine PLT antibody. Statistical analysis was performed using SPSS25.0 Software. Results: A total of 364 patients received 1,060 PLT transfusions, including 728 successful transfusions and 332 unsuccessful transfusions. When the patients were grouped according to different etiologies, significant differences in PLT transfusion effectiveness were observed between these groups (χ² = 15.070, p < 0.05). Grouping of the 364 patients according to sex, blood type, and PLT transfusion frequency showed no significant difference in PLT transfusion refractoriness (PTR) between different age-groups and sexes (p > 0.05). With the number of PLT transfusions increasing, PTR increased gradually. PLT antibodies were detected of 364 patients, 67 of them were positive. Among them, 63 cases (94.02%) were positive for HLA class I antibody. Conclusion: To reduce PTR, multiple factors should be considered comprehensively when PLT transfusion therapy is to be implemented in clinical practice. PLT antibody is the main immune factor causing PTR.

Anti-HLA Class I alloantibodies in platelet transfusion refractoriness: From mechanisms and determinants to therapeutic prospects.

Patients with hematological disorders and severe thrombocytopenia require extensive and iterative platelet transfusion support. In these patients, platelet transfusion refractoriness represents a serious adverse transfusion event with major outcomes for patient care. Recipient alloantibodies against the donor HLA Class I antigens expressed at the cell surface of platelets result in a rapid removal of transfused platelets from the circulation and thus, therapeutic and prophylactic transfusion failure leading to a major bleeding risk. In this case, the only way to support the patient relies on the selection of HLA Class I compatible platelets, an approach restricted by the limited number of HLA-typed donors available and the difficulty of meeting the demand in an emergency. However, not all patients with anti-HLA Class I antibodies develop refractoriness to platelet transfusions, raising the question of the intrinsic characteristics of the antibodies and the immune-mediated mechanisms of platelet clearance associated with a refractory state. In this review, we examine the current challenges in platelet transfusion refractoriness and detail the key features of the antibodies involved that should be considered. Finally, we also provide an overview of future therapeutic strategies.